U.S. patent application number 16/859911 was filed with the patent office on 2020-11-19 for conveyor.
This patent application is currently assigned to Wipotec GmbH. The applicant listed for this patent is Wipotec GmbH. Invention is credited to Stephan Clo ner, Christoph Eckhardt, Jochen Gerlach, Matthias Joachim, Alexander Schulzki.
Application Number | 20200361712 16/859911 |
Document ID | / |
Family ID | 1000005017811 |
Filed Date | 2020-11-19 |
United States Patent
Application |
20200361712 |
Kind Code |
A1 |
Schulzki; Alexander ; et
al. |
November 19, 2020 |
Conveyor
Abstract
A conveyor and process for transporting products, wherein a
carrier with an associated product holder can be moved along a
conveying path by means of a conveyor element. In a processing
position, the carrier can be aligned by means of first alignment
elements, and second alignment elements are provided for aligning
the product holder for disengagement from the carrier.
Inventors: |
Schulzki; Alexander;
(Stelzenberg, DE) ; Joachim; Matthias; (Pirmasens,
DE) ; Clo ner; Stephan; (Ehringshausen, DE) ;
Eckhardt; Christoph; (Breidenbach, DE) ; Gerlach;
Jochen; (Dautphetal, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wipotec GmbH |
Kaiserslautern |
|
DE |
|
|
Assignee: |
Wipotec GmbH
Kaiserslautern
DE
|
Family ID: |
1000005017811 |
Appl. No.: |
16/859911 |
Filed: |
April 27, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65G 17/32 20130101;
B65G 2203/0258 20130101; B65G 17/002 20130101; B65G 2203/0216
20130101; B65G 2811/0621 20130101; B65B 35/10 20130101; B65G
2203/04 20130101 |
International
Class: |
B65G 17/00 20060101
B65G017/00; B65G 17/32 20060101 B65G017/32 |
Foreign Application Data
Date |
Code |
Application Number |
May 3, 2019 |
DE |
202019102508.5 |
Claims
1-20. (canceled)
21. A conveyor for transporting products, the conveyor including:
(a) a product holder adapted to receive at least one product; (b) a
carrier adapted to receive the product holder in a supported
position; (c) a conveying element operable to move the carrier and
product holder received on the carrier in a horizontal conveying
direction to a processing position which is defined within
tolerances with respect to the conveying direction and with respect
to a horizontal transverse direction extending perpendicular to the
conveying direction; and (d) first alignment means for aligning the
carrier in the conveying direction, or the transverse direction, or
both the conveying direction and transverse direction relative to
the conveying element or a fixed component of the conveying
element, to thereby transfer the carrier from the processing
position to a target carrier position.
22. The conveyor of claim 21 wherein the first alignment means
comprises a movable alignment element which is movable to impinge
on the carrier in the processing position to displace the carrier
into the target carrier position.
23. The conveyor of claim 22 wherein the movable alignment element
comprises a bolt extending along a longitudinal bolt axis, the bolt
being movable to contact guide surfaces of the carrier in order to
displace the carrier into the target carrier position.
24. The conveyor of claim 23 wherein the bolt is fixed in position
with regard to the conveying direction and the transverse direction
and wherein the carrier in the processing position is movable in
the conveying direction, or the transverse direction, or both the
conveying direction and transverse direction.
25. The conveyor of claim 21 further including second alignment
means for aligning the product holder in a target product holder
position which is defined in the conveying direction and the
transverse direction.
26. The conveyor of claim 25 wherein the second alignment means
includes alignment surfaces on the product holder which are
configured to mate with surfaces of a centering unit which is
moveable relative to the carrier.
27. The conveyor of claim 26 further including a weigh cell having
a load introduction section supporting the centering unit, the
weigh cell being operable to measure the weight of the product
holder and any product received thereon when the product holder is
released from the carrier.
28. The conveyor of claim 27 wherein the load introducing section
is moveable relative to the product holder in a vertical direction
perpendicular to both the conveying direction and the transverse
direction until the weight force of the product holder and any
product supported on the product holder is released from the
carrier and introduced into the load introducing section.
29. The conveyor of claim 28 further including a lifting mechanism
operable for moving the weigh cell, load introducing section of the
weight cell, and centering unit in the vertical direction until the
product holder and carrier are separated from each other and the
weight force of the product holder and any product supported
thereon is received by the load introducing section of the weigh
cell.
30. The conveyor of claim 29 wherein the first alignment means
includes a bolt which is coupled to the weigh cell such that the
bolt is movable together with the weigh cell in the vertical
direction.
31. The conveyor of claim 30 wherein the alignment of the carrier
or the release of the product holder is carried out as part of a
continuous relative movement between the weigh cell and carrier in
a straight lifting movement of the weigh cell relative to the
carrier and substantially fixed in the plane of the conveying
direction and transverse direction.
32. The conveyor of claim 21 further including at least one
additional carrier, each additional carrier being associated with a
respective additional product holder, and wherein the conveying
element is operable to move the carrier and each additional carrier
along the conveying direction individually or together.
33. The conveyor of claim 32 wherein the carrier and each
additional carrier and the product holder and each additional
product holder is provided with a unique machine-readable mark, via
which individual data can be allocated to the respective carrier or
product holder.
34. The conveyor of claim 21 wherein the product holder is formed
from a material suitable for X-ray radiography such that foreign
bodies contained in the product or a fill quantity of the product
received on the product holder, or both, are detectable by X-ray
radiography of the product holder and the product received on the
product holder.
35. A weighing station including: (a) a product holder adapted to
receive at least one product, the product holder including product
holder alignment surfaces; (b) a carrier adapted to receive the
product holder in a supported position; (c) a conveying element
operable to move the carrier and product holder received on the
carrier in a horizontal conveying direction to a processing
position which is defined within tolerances with respect to the
conveying direction and with respect to a horizontal transverse
direction extending perpendicular to the conveying direction; (d)
first alignment means for aligning the carrier in the conveying
direction, or the transverse direction, or both the conveying
direction and transverse direction relative to the conveying
element or a fixed component of the conveying element, to thereby
transfer the carrier from the processing position to a target
carrier position; (e) a centering unit which is moveable relative
to the carrier, the centering unit including centering surfaces
which are configured to mate with the product holder alignment
surfaces; and (f) a weigh cell having a load introduction section
supporting the centering unit, the weigh cell being operable to
measure the weight of the product holder and any product received
thereon, when the carrier is in the target carrier position and the
product holder is released from the carrier by movement of the
centering unit relative to the carrier.
36. A process including: (a) moving a carrier with a product holder
received thereon along a horizontal conveying direction into a
processing position for the carrier which is defined within
tolerances with respect to the conveying direction and with respect
to a horizontal transverse direction extending perpendicular to the
conveying direction; (b) placing a first alignment element and the
carrier in a contact position relative to each other to align the
carrier in the conveying direction, or the transverse direction, or
both the conveying direction and transverse direction to thereby
transfer the carrier from the processing position to a target
carrier position; and (c) moving the product holder and the carrier
relative to each other in order to release the product holder from
the carrier and to introduce the weight force of the product holder
and any product received thereon into a load introducing section of
a weigh cell.
37. The process of claim 36 further including moving a centering
unit relative to the product holder to bring centering surfaces of
a centering unit into contact with alignment surfaces of the
product holder to place the product holder in a target product
holder position, and wherein the centering unit is supported on the
load introducing section of the weigh cell.
38. The process of claim 37 wherein the first alignment element is
coupled to the weigh cell and wherein the alignment of the carrier
and the release of the product holder are both effected as part of
a relative movement between weigh cell and the carrier in a lifting
movement of the weigh cell relative to the carrier.
39. The process of claim 36 further including one of: (a)
identifying the carrier using a carrier mark located on the
carrier, and determining data relating to the carrier directly or
indirectly from the carrier mark, and aligning the carrier in the
target carrier position using the data relating to the carrier; and
(b) identifying the product holder using a product holder mark
located on the product holder, and determining data relating to the
product holder directly or indirectly from the product holder mark,
and aligning the product holder a target product holder position
using the data relating to the product holder.
40. The process of claim 36 further including weighing the product
holder one or more times and storing data resulting from each
weighing in a database or a writeable memory device located on the
product holder or the carrier.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to conveyors for transporting
products, particularly to one or more processing stations. The
present invention also relates to processes for aligning conveyed
products for processing.
BACKGROUND OF THE INVENTION
[0002] Industrial facilities for the production or packaging of
goods often comprise conveyor lines along which the goods are
transported successively to different processing stations. Such
processing stations can include in particular sorting machines,
weighing machines, packaging and inspection machines and marking
devices. Further devices known to a person skilled in the art are
also conceivable for handling the products appropriately depending
on the desired processing.
[0003] The products are moved to the individual processing stations
by means of a conveyor. Special conveying members (drivers, hooks
etc.) are moved along a conveyor element, for example a rail, in a
conveying direction and can themselves be coupled to individual
carriers. Each carrier is formed to receive one or more products.
It is also possible for a carriage or cart, or a group of carriages
or carts, driven by a conveyor chain or a cable, to serve as a
carrier. Products may be received indirectly or directly such a
carrier for transporting the products into the individual
processing stations and out again, for example.
[0004] The carriers transported along the conveyor line are usually
tailored to the goods to be transported in each case and have
particular contours or dimensions in order to be able to receive
and transport the goods securely. The carriers can be connected to
the conveying members by simple insertion, screwing, snapping-in
etc. The carrier makes it possible to transport different products
with the same conveyor by, for example, the upper area of the
carrier being formed to receive different products, while the
underside is formed to couple to the members of a conveying
device.
[0005] It is further known to provide specific product holders for
the individual carriers. The product holders can be placed on the
carriers or inserted into them and serve to directly receive the
product to be transported. A product holder can be formed for
laying sausage or cheese slices on, for example. Product holders
for receiving pourable or free-flowing products are also known.
[0006] The carriers mainly have the task of transporting goods
along the conveyor line without there being particular requirements
for the highly precise positioning of the carriers during the
transport or also at the individual processing stations. As a rule,
it is sufficient to position the goods transported by the carriers
in the individual processing stations within presettable rough
tolerances in order, for example, to be able to package the
products there or radiograph them for inspection purposes. If the
carriers are transported along a rail, for example, as a rule the
positioning accuracy which results from the coupling between the
rail and the carrier is sufficient in the individual processing
stations. Positioning inaccuracies can result due to an existing
mechanical play between rail and carrier transverse to the
conveying direction (sometimes referred to as the "Y direction" in
the following). Positioning tolerances can also occur in the
conveying direction (sometimes referred to as the "X direction" in
the following), for instance when the carriers are driven by a
chain with play, a gear mechanism or a spindle. Such positioning
tolerances are acceptable for a range of processing stations.
[0007] However, difficulties arise when the products in a
processing station need to be positioned very precisely in the
space. This applies, for example, to a processing station designed
as a weighing machine, with which the weight of the goods
transported by the carriers is to be measured. In order to be able
to weigh a product in a processing station formed as a weighing
machine, it is expedient to "release" the product (possibly
together with a known preload). By this is meant the situation
where the weight force of the product (possibly with preload) is
introduced fully into the load receiver of a weigh cell of the
weighing machine without a positive-locking or friction-locking
connection remaining between the product and a component not to be
weighed with it, a carrier for example.
[0008] In practice, the product holder received by the carrier
often forms a preload and is thus weighed together with the
product. For weighing, the product holder must therefore be
completely decoupled ("released") from the carrier allocated to it
in order to prevent a force shunt and thus a distorted weighing
result.
[0009] In order to reliably achieve the release of the product
holder from the carrier, first of all the position of the carrier
in the space, in particular in the X-Y plane, must be preset or
known within narrow tolerances so that the product holder can be
lifted out of the carrier as centrally as possible during the
subsequent release, without tilting or shifting in the process.
Only then can the release be achieved by a relative movement
between the carrier and the product holder which is as simple,
small and quick as possible. The rough tolerances with which
carriers known from the state of the art are moved along the
conveyor line are therefore unsuitable for aligning the product
holders transported with the carriers sufficiently precisely.
SUMMARY OF THE INVENTION
[0010] An object of the invention is to provide a device and a
process with which the carriers can be aligned so precisely that a
subsequent release of the product holder relative to the carrier is
possible simply and quickly.
[0011] According to one aspect of the invention a first alignment
means is provided for aligning the carrier by transferring a
carrier which has entered a processing position along the conveyor
line into a presettable target carrier position. This alignment
occurs by impingement on and movement of the carrier relative to
the conveyor or another component, which is fixed in the space at
least with regard to its position in a horizontal plane. In
addition to the only rough positioning which the carrier
experiences via its coupling to the components of the conveyor, the
first alignment means according to the invention guarantees the
transfer of the carrier which has entered the processing position
into the precisely presettable target carrier position. The carrier
can thus be displaced and/or tilted relative to the conveyor or a
component connected thereto in order to make it possible to
subsequently, and in a simple manner, release the product holder
received by the carrier. The coupling between the conveyor and the
carrier is preferably chosen within rough tolerances such that the
precise alignment of the carrier brought about by the first
alignment means ranges within these tolerances.
[0012] The first alignment means, which is formed at least
partially movable, expediently comprises at least one movable
alignment element. For alignment, the alignment element can impinge
on and displace or tilt the carrier after reaching the processing
position. The alignment element expediently has contact surfaces
which engage with the carrier when the alignment element moves
relative to the carrier and, as the movement is continued, exert
forces on the carrier in order to displace and/or tilt it into the
desired target carrier position.
[0013] The movement of the first alignment means relative to the
carrier can be effected, for example, by a linear drive or another
electromechanical drive means known to a person skilled in the art.
The alignment can also occur utilizing the movement of the carrier
along the conveying path, for instance by lateral guide means
impinging on the carrier as it moves into the processing position.
The precise alignment of the carrier in the X direction can be
achieved, for example, by a limit stop at the processing position
which can be pivoted into the conveying path. After reaching the
limit stop, the carrier is also precisely positioned in the Y
direction because of the lateral guide means. An alternative
embodiment, preferred in the following, in contrast provides that
the first alignment means do not cooperate with the carrier until
it has reached the processing position and is already pausing
there. In this case, the processing position is only defined within
rough tolerances, and the carrier can still be displaced in
particular in the X and in the Y direction.
[0014] Some embodiments of the invention may provide that the first
alignment means comprises at least one bolt formed about a
longitudinal axis, which, for alignment of the carrier, can be
moved in against a guide surface on the carrier, preferably into a
recess or into an opening or hole in the carrier. The bolt and the
guide surfaces on the carrier cooperating with it are designed such
that a movement of the bolt in a first direction (in particular in
a direction Z perpendicular to the X-Y plane) simultaneously aligns
the carrier in the two directions X and Y perpendicular to the Z
direction. This can be advantageously achieved by the bolt having a
conical tip, which is introduced into the recess in the carrier,
wherein, as the Z height of the bolt increases, the conical surface
approaches the contact surfaces of the recess in the carrier until
they touch, in order to then exert horizontal displacement forces
from the conical surface of the bolt onto the contact surfaces of
the carrier and to displace the carrier accordingly. The bolt is
preferably fixed with regard to its X and Y position, whereas the
carrier is variable, and thus can be aligned, in the X-Y plane,
thus also relative to the conveyor, to the required extent. Several
bolts or comparable alignment elements spaced apart from each other
can simplify the alignment of the carrier further, since a specific
rotational position in the X-Y plane is thus also presettable.
[0015] Embodiments of the invention may further provide a second
alignment means which is operable to transfer (release) the product
holder into a presettable target product holder position relative
to the carrier, which is defined at least with respect to its X and
Y position. It is thus possible according to the invention, after
previously aligning the carrier in the space, now to release the
product holder from the carrier in order to carry out the weighing
procedure.
[0016] Whereas the first alignment means serves to align the
conveyor's carrier, which is not also to be weighed, precisely in
the space for the later release of the product holder, the second
alignment means preferably serves to release the product holder
relative to the carrier. Alternatively, however, it can also be
enough to actuate only the second alignment means to completely
release the product holder in the carrier if the processing
position taken up only within rough tolerances by the carrier is
sufficient in any case to reliably bring about the release of the
product holder from the carrier.
[0017] Alignment surfaces or contours (also referred to herein as
contact surfaces) may be provided on the product holder which are
formed for interaction with a centering unit moved relative to the
product holder. The centering unit and alignment surfaces together
form the second alignment means. The second alignment means can be
formed analogous to the first alignment means such that, as part of
a relative movement between centering unit and product holder,
contact surfaces of both components approach each other and touch,
in order, in particular in the X-Y plane, to exert forces on the
product holder and align it. For example, on a side facing the
carrier, the product holder could be provided with conically
running surfaces which cooperate with suitable guide surfaces or
edges of the carrier and thus position the product holder precisely
in the carrier and relative to it.
[0018] Alternatively, however, it is also conceivable to form the
second alignment elements simply as stop elements acting against
each other, which are used to lift the product holder out of the
carrier. If the product holder is arranged in the carrier such that
a mechanical separation of the product holder from the carrier is
simultaneously achieved by vertically lifting the product holder
out of the carrier, this is already enough for the release. In this
case, the centering unit is not used for centering (thus for the
horizontal alignment of the product holder relative to the
centering unit), but merely for raising the product holder in the Z
direction, without the position of the product holder in the space
being changed in the X or Y direction.
[0019] Some embodiments of the invention may further include a
weigh cell, which is formed to measure the weight of a product
holder which is loaded with product or unloaded and, in the
processing position, is released from its associated carrier,
wherein the weigh cell has a load introducing section, comprising
the centering unit, for introducing the load to be weighed into the
weigh cell. The weigh cell has the task of weighing the products
transported along the conveying path. For this purpose, the product
holders receiving the products must be released in the manner
described above. The weight force to be determined is introduced
into the load introducing section of the weigh cell by the product
holder and is converted into an analyzable signal by a mechanism
known to a person skilled in the art inside the weigh cell.
[0020] The load introducing section preferably includes the
centering unit, with which the product holder is released relative
to the carrier. The product holder is then released by first of all
aligning the carrier in the space by the first alignment means. As
part of this alignment, the carrier (with the product holder
received by it) is aligned in the processing position such that the
product holder is positioned relative to the centering unit for the
subsequent releasing procedure such that the release can be
effected solely with the aid of a relative movement between
centering unit and product holder. The weigh cell, with its load
introducing section including the centering unit, is formed
displaceable to the extent that the weight force of the product
holder is introduced into the load introducing section free of
force shunt (release) or is decoupled therefrom (the product holder
rests on the carrier).
[0021] The releasing procedure can preferably be effected such that
the weigh cell, with its load introducing section and the centering
unit arranged thereon, is moved towards the product holder in order
to thereby receive the product holder and to disengage it from the
carrier. For this purpose, the weigh cell is expediently arranged
on a lifting device, with the result that it is movable (preferably
from below), with its load introducing section, upwards towards the
product holder in order to lift the latter out of the carrier. In
the reverse motion sequence, the weigh cell descends again, with
the result that the product holder is received by the carrier
again. As soon as the centering unit is separated sufficiently far
from the product holder and, if necessary, the first alignment
means has also been disengaged from the carrier, the carrier
together with the product holder can be moved along the conveying
path to the next processing station.
[0022] Alternatively, the product holder could also be lowered onto
a substantially fixed weigh cell. However, the result of this would
be that the carrier carrying the product holder would also have to
be lowered with it, which is difficult in terms of construction,
but not impossible.
[0023] According to some embodiments of the invention, the conveyor
is formed such that the release is brought about through alignment
of the carrier in the space by means of first alignment elements,
with alignment or release of the product holder relative to the
carrier by means of the second alignment elements following this or
overlapping in time or simultaneously. An implementation of the
invention may provide that one part of the first alignment elements
(in particular the above-named bolt) is fixedly, or largely
fixedly, coupled to the weigh cell, with the result that these
alignment elements engage with the carrier to be aligned through
preferably vertical movement of the weigh cell and align it or
transfer it into the target carrier position. In this case, parts
of both the first alignment means (for example the bolt) and the
second alignment means (namely the centering unit) are arranged on
the weigh cell. The first alignment means thus cooperate with the
carrier, through an in particular vertical raising or lowering of
the weigh cell, in order to align it in the space, while, at the
same time or offset in time, the centering unit cooperates with the
product holder in order to lift it out of the carrier.
[0024] The alignment of the carrier carrying the product holder in
the space or relative to the X-Y position of the weigh cell allows
the weight force of the product holder (with or without products
lying thereon) to be introduced into the load introducing section
of the weigh cell precisely and without interference during the
later release. For the avoidance of corner loads, as part of the
release movement, it is therefore sought to move the load
introducing section towards a precisely defined coupling section of
the product holder. The previous precise alignment of the carrier
with the first alignment means ensures that the load introducing
section cooperates with the product holder at the coupling section
provided and is not spaced apart to the side of it, for
instance.
[0025] For the purposes of the release, the coupling of the product
holder to the load introducing section is preferably effected such
that the product holder merely lies loosely on the load introducing
section. Through a vertical relative movement between the load
introducing section and product holder, these two components can
then be coupled to each other to transfer the weight force or be
decoupled from each other to disengage the weight force.
[0026] Some embodiments of the invention provide that the alignment
of the carrier in the space and the release of the product holder
relative to the carrier is achieved as part of a (preferably
continuous) relative movement between weigh cell and carrier. In
the process, the weigh cell can be moved, with a part of the first
alignment means secured to it or moved together with it, preferably
with a bolt, from below in the Z direction towards a carrier
arranged in a processing position. During the upwards movement,
this part of the first alignment means comes into contact with
further parts of the first alignment means, which are arranged on
the carrier. As part of the upwards movement, the carrier is
aligned in the X and Y direction relative to the weigh cell through
this contact. As part of the alignment means, a bolt which can
engage in a recess formed in the carrier is preferably secured to
the weigh cell, with the result that the carrier is aligned
relative to the weigh cell and thus in the space in the manner
described above.
[0027] In the further upwards movement, the bolt slides further
upwards through the named recess without additional interaction
with the carrier, while the centering unit arranged on the load
introducing section of the weigh cell moves towards the product
holder arranged in the carrier from below. The centering unit
engages underneath the product holder and, in the further upwards
movement of the weigh cell (if necessary with the aid of suitable
guide surfaces), aligns it relative to the carrier such that the
product holder is lifted out of the carrier and released from the
carrier. Since the alignment of the carrier and subsequently the
release of the product holder can be effected as part of a single
movement of the weigh cell relative to the carrier, the product
delivered into the processing station can be weighed promptly. The
release of the product for onward transport, thus the lowering of
the weigh cell for reinsertion of the product holder into the
carrier and the subsequent release of the carrier (decoupling of
the first alignment means), can also be effected by a single
relative movement, this time in the opposite direction, between
weigh cell and carrier and can accelerate the processing process
advantageously.
[0028] The relative movement between weigh cell and carrier is
preferably linear, thus along a straight path. With a suitable
design of the first and second alignment elements, however, a
curved or otherwise suitable spatial path, along which the weigh
cell is moved relative to the carrier in order to bring about the
alignment and release, is also conceivable.
[0029] A conveyor in accordance with the present invention may
include several carriers, wherein each carrier can receive one or
more product holders. The carriers and/or their product holders are
preferably provided with a mark from which, for example, the
geometric properties of the respective carrier or product holder
can be derived, for example via a control unit with access to a
database. If the mark of the carriers or product holders is read
automatically by suitable sensors along the conveyor line, an
automated alignment procedure can be adapted to the product
holder/carrier. This can relate to the desired upstroke of the
weigh cell or of a pneumatic cylinder or of a linear drive, for
example, in order to be able to specify the lifting height required
for the alignment or release depending on the constructive design
of the carrier or of the product holder.
[0030] In come embodiments, several carriers can be moved along the
conveying path together. Several product holders, which are
allocated in each case to one of the carriers, can thereby be
transported simultaneously, which increases the throughput of the
facility. Through suitable arrangement of several weigh cells in a
processing station set up for weighing, several product holders
(with or without product lying thereon) can thus also be weighed at
the same time. The features described above for one carrier then
also apply correspondingly to the other carriers. If the carriers
enter a processing station formed for weighing, then a dedicated
weigh cell with load introducing element is preferably provided
there for each carrier or at least for each product holder, with
the result that each weigh cell can measure the weight of the
product holder of one of the carriers.
[0031] The relative movement between the respective product holder
and the load introducing element or weigh cell can be effected by
moving the weigh cells up or down together relative to the several
product holders in the individual carriers. Alternatively, however,
an individual relative movement between the respective weigh cell
and the associated carrier or product holder can also be effected,
which increases the flexibility of the procedure within the
processing station.
[0032] Where several carriers are moved together they may be
arranged next to each other in the conveying direction or
transverse thereto, or in the form of a row and column matrix.
Several product holders can thus be weighed quickly in a
comparatively narrow space.
[0033] In some implementations of the invention, the different
carriers of the conveyor and/or their product holders are each
provided with a unique mark. This mark is to make it possible to
identify and to individualize the carrier and/or the product
holder. Specific properties of the carrier and/or of the product
holder can thereby be measured and, for example, transmitted to a
higher-level control in order to take them into account during the
operation of the conveyor. This can, for example, relate to the
empty weight (tare). Every product holder has such an individual
empty weight, which is to be taken into account during the
weighing. The individual mark makes it possible to determine the
empty weight of the respective product holder for this purpose. The
empty weight can be contained directly in the mark itself or be
determined, using the mark, from a database which establishes the
relationship between the mark and the empty weight.
[0034] The mark can be non-variable identification means, such as
for example a barcode or a number or a fixed RFID mark.
Alternatively or in addition, the mark can also be variable, for
instance in order to store specific, possibly also variable,
properties of the carrier or product holder directly in the mark.
For example, a code for the empty weight of a product holder could
be stored in a memory arranged on the product holder as a mark or
part of a mark. If the mark is read in the process, a control unit
controlling the process obtains data about the empty weight of the
product holder directly from the mark in order to take this into
account during the weighing.
[0035] Variable marks have the advantage that they document changes
in the carrier or the product holder directly on the component
itself, without a special database having to be edited for this
purpose. If, for example, the empty weight of a (then unloaded)
product holder is determined by means of one or more weighing
procedures, then a code representing this value can be written
directly into the variable mark on the product holder. As part of a
regular weighing process with product lying on the product holder,
the empty weight can be determined by reading the mark and
subtracted from the total weight determined by the weigh cell, in
order to obtain the product weight (net).
[0036] Alternatively, of course, the empty weight can also be
stored in a database, from which the control unit allocates the
empty weight via the mark identified on the product holder. Any
other desired properties of a carrier or product holder (geometric
dimensions, material properties, time or location data etc.) can
also be stored directly in the mark or a database, which allocate
the properties to the mark.
[0037] It is further conceivable to allocate the properties of
several carriers and/or product holders to a common mark, for
instance when several carriers are coupled to form a group and are
moved along the conveyor line together. Then, properties of the
individual carriers and/or of the product holder associated with
each carrier could be stored in the common mark or allocated to it.
Using the mark, a distinction is then to be possible between the
individual carriers or product holders, in order to be able to read
or derive from the mark the property of a particular product holder
or carrier within the group. Thus, a group formed, for example, of
four carriers each with one product holder could have a common,
writable RFID chip. Data for each carrier and/or product holder can
be stored in the chip. The reading and writing of such a memory are
then simplified since only one mark needs to be read for all four
carriers or product holders. Only one read unit or write unit then
needs to be provided to read data for a control unit or to store it
in the memory of the RFID chip for all four carriers or product
holders. Other readable and/or writable identification means
sufficiently known to a person skilled in the art are also
conceivable for identifying one or more carriers or product holders
and for making the allocation of specific properties possible.
[0038] The material of the product holder is preferably suitable
for X-ray radiography. Then, the product holder and a product lying
on the product holder can be radiographed by means of X-rays in
order to be able to detect any foreign bodies contained therein. It
is also possible to measure a fill quantity of a product when the
intensity of the X-radiation is influenced by the fill level, for
instance in the case of a filled yoghurt pot lying on the product
holder. In general, the radiographable product holder is to make it
possible to measure fill quantities, fill levels or nominal fill
quantities with the aid of X-ray radiography. Monitoring the fill
level or tests for foreign bodies possibly contained in the product
can be carried out in an X-ray inspection unit arranged along the
conveyor line, which can be arranged upstream or downstream of a
processing station formed as a weighing station.
[0039] A conveyor according to the invention preferably comprises
at least one weighing station with at least one weigh cell, in
order to measure weight forces in the manner described above.
[0040] The process for releasing a product holder in the device
described above may comprise the following steps: [0041] a) moving
a carrier with a product holder received therein into the
processing position, [0042] b) aligning the carrier by means of
first alignment means into a target carrier position, [0043] c)
moving (releasing) the product holder and the carrier relative to
each other in order to disengage the product holder from the
carrier and to introduce the weight force of the product holder,
loaded with product or unloaded, into the load introducing section
of a weigh cell.
[0044] The carrier preferably reaches the processing position in a
substantially horizontal movement (X-Y plane). However, that does
not rule out this movement also comprising a Z component, for
instance when the conveying path is directed upwards or downwards.
In the processing position, in which the empty product holder or
one carrying a product is to be weighed, the carrier rests
substantially fixed in position in relation to its X and Y
coordinates. Small displacement possibilities exist in the X and/or
Y direction, however, in order to be able to position the carrier
precisely, with regard to its desired X-Y position, in the
presettable target carrier position with the aid of the first
alignment means.
[0045] The release of the product holder relative to the carrier
may be effected perpendicularly to the X-Y plane by lifting the
product holder out of the carrier. This can be downstream of the
positioning of the carrier in the target carrier position. However,
the two positioning procedures preferably overlap in order to save
time. The release of the product holder relative to the carrier can
even already be finished while the carrier is still being
transferred into the target carrier position by the first alignment
means. It is also conceivable to already bring the second alignment
means into engagement on or with the product holder before the
first alignment means interact with each other. Accordingly, the
product holder could already be lifted out of the carrier by an
amount before the carrier itself is aligned. The release of the
product holder is then effected at the latest as part of the
transfer of the carrier into the target carrier position, since the
positioning of the carrier in the X-Y direction hereby produces
enough lateral spacing from the product holder for weighing without
force shunt.
[0046] The alignment of the carrier and the release of the product
holder are preferably effected within a continuous relative
movement between weigh cell on the one hand and carrier or product
holder on the other hand, most preferably as part of a purely
vertical and/or straight upwards movement of the weigh cell
(through the formation of suitable alignment elements, relative
movements inclined with respect to the X, Y spatial axes can also
make the alignment of the carrier and, respectively, the release of
the product holder possible).
[0047] In processes according to the present invention, first
alignment elements arranged on the weigh cell, such as a vertical
bolt for example, may engage, as part of this movement, in a recess
in the carrier provided for this purpose and bring about the
horizontal alignment of the carrier through suitable contact
surfaces. As part of the upwards movement, second alignment
elements arranged on the load introducing section of the weigh cell
cooperate with suitable contact surfaces on the product holder in
order to align it relative to the carrier and thus to be able to
achieve the release within a single movement of the weigh cell.
[0048] After the product holder has been released from the carrier,
the product holder rests exclusively on the load introducing
section of the weigh cell, with the result that the weight of the
product holder can be measured. By reversing the releasing
movement, the product holder comes back into engagement with the
carrier and can, after any remaining couplings of first or second
alignment elements are disengaged, be moved further in the
conveying direction in order to be able to transfer a subsequent
carrier into the processing position.
[0049] These and other advantages and features of the invention
will be apparent from the following description of representative
embodiments, considered along with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a simplified perspective view of a device
embodying principles of the invention with a carrier in a
processing position.
[0051] FIG. 2 is a side view of the device shown in FIG. 1 with the
carrier in the same position as that shown in FIG. 1.
[0052] FIG. 3 is a side view similar to FIG. 2 but with the weigh
cell and elements mounted thereon in a second position relative to
the carrier.
[0053] FIG. 4 is a side view similar to FIG. 2 but with the weigh
cell and elements mounted thereon in a third position relative to
the carrier.
[0054] FIG. 5 is a simplified perspective view similar to FIG. 1
but showing the weight cell and elements mounted thereon in the
same position relative to the carrier as shown in FIG. 4.
DESCRIPTION OF REPRESENTATIVE EMBODIMENTS
[0055] FIG. 1 shows, in a simplified perspective view, the
essential components of a conveyor according to the invention. A
carrier T is movable in a conveying direction G along a fixed
conveying element M formed as a rail. The carrier T carries a
product holder P on which a product R (shown only in the side views
of FIGS. 2-4) can lie in order to move the product R along a
production line. The product holder P can be lifted out of the
carrier T upwards in the Z direction. Not represented in more
detail are driven conveying members (for example drivers, chain
links or hooks), which can displace the carrier T along the
conveyor element M.
[0056] A schematically represented weigh cell W is arranged
underneath the conveyor element M. The weigh cell W comprises an
angled load introducing section L, which itself carries a centering
unit F, which is positioned substantially underneath the base E of
the product holder P. Via the load introducing section, the weight
of the product holder P can be introduced into a weighing mechanism
(not represented in more detail) in the weigh cell W in order to
generate an analyzable weighing signal therefrom. All weighing
mechanisms known to a person skilled in the art, also independently
of the present examples in the figures, can be used to generate the
weighing signal, wherein the principle of electromagnetic force
compensation is to be mentioned in particular.
[0057] The weigh cell W can be moved upwards and downwards in a
lifting direction H, and thus relative to the conveying element M,
via a lifting mechanism W.sub.L (shown only in the side views of
FIGS. 2-4). In this embodiment example, the lifting direction H
coincides with the vertical Z axis.
[0058] In FIG. 1, the carrier T has reached a processing position
X.sub.B along the conveying element M and rests there at first.
Within this processing position X.sub.B, the carrier T has to be
transferred into a target carrier position which is precisely
presettable in particular through its X and Y coordinates. This is
necessary in order to be able to ensure the release of the product
holder P from the carrier T. For this purpose, the device has first
alignment means A.sub.T, which is formed partly on the carrier T
and partly on the weigh cell W. In this example the portion of the
first alignment means formed in the carrier T comprises an
alignment opening V in the form of a hole on the carrier, the axis
of opening V running in the Z direction. Underneath the carrier
arranged in the processing position and on the top of the weigh
cell W, a cylindrical bolt D is formed about an axis D.sub.Z, which
also extends in the Z direction and comprises the portion of the
first alignment means formed on the weigh cell W. The external
diameter of the bolt D is chosen slightly smaller than the internal
diameter of the alignment opening V. At its upper end, the bolt D
is provided with a conical section, which makes threading into the
alignment opening V easier and at the same time brings about the
alignment of the carrier T relative to the bolt in the X-Y
plane.
[0059] In the present example, the centering unit F has a pyramid
section with conically tapering outer surfaces at its upper end.
These are part of second alignment means A.sub.P, with which the
product holder P is released from the carrier T. The base E of the
product holder P is open at the bottom and designed with inner
surfaces (shown best in FIGS. 2-4 as the hidden lines in base E),
which also form part of the second alignment means A.sub.P. By
raising the centering unit F into the base E of the product holder
P from below, the inner surfaces of the base come into contact with
the pyramid section, whereby the base is initially aligned in the
horizontal direction (X-Y plane) relative to the centering unit F
and thus to the weigh cell W. With a continued upwards movement of
the centering unit F, the latter eventually engages underneath the
base E in a positive-locking manner. Then, a further movement of
the product holder P relative to the centering unit F is no longer
possible and the product holder P is lifted out of the carrier T by
the centering unit, raised further with the weigh cell.
[0060] The spatial arrangement of the weigh cell W with the bolt D
and the centering unit F is chosen such that, in a substantially
straight, preferably continuous upwards movement of the weigh cell
W, first of all the carrier T is aligned via the bolt D and then
the product holder P is lifted out of the carrier T such that the
product holder P lies on the load introducing section L without
force shunt and thus introduces its full weight into the weigh cell
W. The arrangement of the bolt D and the centering unit F with
respect to each other thus also determines the position of the
carrier T relative to the product holder P at the moment of the
release. In the following figures, the alignment or release is
illustrated with schematic side views.
[0061] FIG. 2 shows how the weigh cell W is raised in the direction
H relative to the conveying element M with the carrier T resting on
it and the product holder P in turn resting thereon. The bolt D is
on the verge of engaging in the alignment opening V of the carrier
T. The centering unit F is not yet in contact with the base E of
the product holder P.
[0062] In FIG. 3 it can be seen how the weigh cell has been moved
further upwards, wherein the bolt D has been pushed into the
alignment opening V and through it. The carrier T has thereby taken
up a precisely defined X-Y position relative to the bolt D or the
weigh cell W, and thus also relative to the centering unit F.
Meanwhile, the centering unit F has come into contact with the
inner sides of the base E of the product holder P from below,
whereby the product holder P has also taken up a precisely preset
X-Y position relative to the weigh cell W. However, the product
holder P is still resting at least partly on the carrier T.
[0063] FIG. 4 shows that the weighing machine W has been fully
raised in the vertical direction H. Here, the bolt D has been
pushed further through the alignment opening V without altering the
X-Y position of the carrier further. Meanwhile, the centering unit
F has engaged fully underneath the base E of the product holder P
and lifted the product holder P out of the carrier T. The product
holder P thus rests exclusively on the load introducing section L
of the weigh cell W, with the result that the weight of the product
holder (with or without product lying thereon) can be measured by
the weigh cell. During the weighing procedure, the carrier T is
secured in the horizontal direction by the bolt D, with the result
that, in the subsequent downwards movement of the weigh cell W (not
represented in more detail), the product holder P can be inserted
back into the carrier T in order to transport it further.
[0064] FIG. 5 shows the situation according to FIG. 4 in a
simplified perspective view.
[0065] FIGS. 2-4 also show that both the carrier T and the product
holder P may include a mark as described above in the summary
section. In particular, the carrier T includes a mark shown
schematically at B.sub.T, while product holder P includes a mark
shown schematically at B.sub.P.
[0066] As used herein, whether in the above description or the
following claims, the terms "comprising," "including," "carrying,"
"having," "containing," "involving," and the like are to be
understood to be open-ended, that is, to mean including but not
limited to. Also, it should be understood that the terms "about,"
"substantially," and like terms used herein when referring to a
dimension or characteristic of a component indicate that the
described dimension/characteristic is not a strict boundary or
parameter and does not exclude variations therefrom that are
functionally similar. At a minimum, such references that include a
numerical parameter would include variations that, using
mathematical and industrial principles accepted in the art (e.g.,
rounding, measurement or other systematic errors, manufacturing
tolerances, etc.), would not vary the least significant digit.
[0067] Any use of ordinal terms such as "first," "second," "third,"
etc., in the following claims to modify a claim element does not by
itself connote any priority, precedence, or order of one claim
element over another, or the temporal order in which acts of a
method are performed. Rather, unless specifically stated otherwise,
such ordinal terms are used merely as labels to distinguish one
claim element having a certain name from another element having a
same name (but for use of the ordinal term).
[0068] Any use of terms indicating orientation, position, or
relative position such as "up," "down," "above," and "below" for
example, are made with reference to the orientation of the
drawings.
[0069] The term "each" may be used in the following claims for
convenience in describing characteristics or features of multiple
elements, and any such use of the term "each" is in the inclusive
sense unless specifically stated otherwise. For example, if a claim
defines two or more elements as "each" having a characteristic or
feature, the use of the term "each" is not intended to exclude from
the claim scope a situation having a third one of the elements
which does not have the defined characteristic or feature.
[0070] The above described preferred embodiments are intended to
illustrate the principles of the invention, but not to limit the
scope of the invention. Various other embodiments and modifications
to these preferred embodiments may be made by those skilled in the
art without departing from the scope of the present invention. For
example, in some instances, one or more features disclosed in
connection with one embodiment can be used alone or in combination
with one or more features of one or more other embodiments. More
generally, the various features described herein may be used in any
working combination.
LIST OF REFERENCE CHARACTERS
[0071] A.sub.p second alignment means [0072] A.sub.T first
alignment means [0073] B.sub.P mark on product holder P [0074]
B.sub.T mark on carrier T [0075] D bolt [0076] D.sub.z axis of the
bolt [0077] E base of the product holder P [0078] F centering unit
[0079] G conveying direction [0080] H vertical direction [0081] L
load introducing section [0082] M conveying element [0083] P
product holder [0084] R product [0085] T carrier [0086] V alignment
opening [0087] W weigh cell [0088] W.sub.L lifting mechanism [0089]
X, Y, Z spatial coordinates [0090] X.sub.B processing position
* * * * *